Phase 9 Study Guide - Part 1

the nominal size of copper water tubing is______ then it's outside diameter

1/8" less

the taper rate for tapered pipe threads is 1 units of diameter for every _______ units of length

16 units

if the systems recommended testing pressures are not known, the pressure should not exceed ________ when testing with carbon dioxide or nitrogen

170 PSIG

what is the superheat of a system with a suction line temperature of 52 degrees Fahrenheit, low side pressure corresponding to 34 degrees Fahrenheit, and a liquid line temperature of 100 degrees Fahrenheit

18 degrees F

per FDA requirements, food storage equipment should maintain food temperature at or below what temperature at all times

41 degrees F

according to the US Department of Agriculture hot foods must be cooled down to what after 4 hours

41° f

a standard single flare on copper tubing is made at a ____ angle

45 degree

the minimum radius for a tubing Bend is how many times the diameter of the tubing

5

a refrigeration system is leak free if deep if deep vacuum pressure holds steady around _______ or less

500 microns

it's a flare fitting connect 3/8 in tubing to 7/16 in tubing, it is called a _________ reducing fitting

7/16 inch to 3/8 inch

according to the US Department of Agriculture, hot foods must be cooled down to what after 2 hours

70° f

tubing should always be cut at an angle of

90 degrees

stop valve to front seat when performing a pump down is the

King valve

the calibration screw on a crankcase pressure regulator is adjusted According to which compressor rating

RLA -rated load amperage

a system leak might be indicated by

a lack of cooling, low suction and head pressure

plastic tubing used in refrigeration related work includes the following

abs, cpvc, pvc

the main task of a dryer is to

absorb moisture and other contaminants that could mix to create acids

superheat may be described as the amount of heat

added to refrigerant after it has evaporated

a type of tubing commonly used to form evaporators and is less costly than copper is

aluminum tubing

when using an external spring to bend soft ACR tubing that will be connected to a flare connector, remember to

bend the tubing before flaring

the system specifically designed to reduce the temperature of cooked food to Frozen storage temperature is a

blast freezer

a vacuum causes moisture in a system to evaporate by lowering the pressure in the system, which in turn lowers the ________ of any moisture in the system

boiling point

with a horizontal joint, begins soldering by touching the solder to the _______ of the joint

bottom

a hot gas bypass valve is primarily used for

capacity control

the sizing of a filter drier is primarily based on a systems

capacity rating

the movement of the liquid substance between two solid substances do to the adhesive forces of the solids overcoming the liquids cohesive forces describes

capillary action

cryogenic food freezing is most commonly done using liquid ______

carbon dioxide and nitrogen

used for topping off a system a ________ cylinder holds a small amount of refrigerant, usually around 5 lbs or less

charging cylinder

a valve that allows fluid flow in Only One Direction is a

check valve

devices used for refrigerant flow control include the following

check valves, pressure regulating valve, solenoid valves

as crankcase pressure Rises, a crankcase pressure regulator does what

closes

the purpose of a CPR is to prevent

compressor motor overload

the four major components of a mechanical refrigeration system are

compressor, condenser, evaporator, and refrigerant metering device

a liquid receiver is a tank connected between the _______ that is used for refrigerant storage

condenser and liquid line

in a commercial refrigeration system that pumps down during the off cycle what controls the liquid line solenoid valve

cooling thermostat

the most common type of tubing used in refrigeration system is

copper

a hot gas defrost valve directs refrigerant into the low side from the

discharge line

true or false CPVC cement should be used to join schedule 40 PVC pipe

false

true or false during passive recovery raising the temperature of a recovery cylinder causes more refrigerant to flow from the system into the cylinder

false

true or false if solder does not melt on contact with the heated joint use the torch to melt the solder directly

false

true or false shut-off valves are made so that only a refrigeration service valve wrench can be used to turn them

false

true or false soldering is commonly used to connect tubing that carries refrigerant

false

true or false? Copper water tubing is basically the same as copper ACR tubing, so technicians can safely use either tubing interchangeably for either purpose

false

a flaked ice evaporator

fills its cylindrical evaporator with water until ice builds up

a device used to maintain proper refrigerant quality is the

filter drier

when retrofitting a refrigeration system from one refrigerant to another, what will need to be replaced

filter drier, lubricant, refrigerant metering device

checking refrigerant charge by superheat is normally done on systems using

fixed orifice metering devices

the paste or powder that prevents oxide from forming an AIDS solder flow is called

flux

most commercial display cases now use ________ evaporators for cooling

forced draft

a relief valve with a metal core that melts at a low temperature is a

fusible plug

black steel pipe in refrigeration related work is generally used for conveying

gas

valves are generally used to protect against High

head pressure

ACR tubing that is type K is______ wall

heavy

if a vacuum must be pulled for a long time and must be left unattended by a technician, it is a good practice to install a solenoid valve between the system and the vacuum pump. Such a solenoid valve should be wired _______ with the vacuum pump.

in parallel

in Commercial Refrigeration, an air curtain is used to

isolate a conditioned space

checking a systems refrigerant charge is important because an improper charge can

lead to compressor damage, reduce system capacity and efficiency, and waste electrical energy

the quickest method of refrigerant charging is

liquid charging

a refrigeration system with an outdoor air-cooled condenser that does not have head pressure control will likely suffer from

low or no subcooling

when brazing to repair a system leak, the nitrogen should be ______ in order to create a good brazed joint

low pressure and flowing

the primary purpose of evaporator pressure regulators epr's on multiple evaporator systems is to

maintain different evaporator temperatures

ACR tubing that is L Type is _____ wall

medium

the type of torch flame that is the most efficient to use when brazing is the

neutral Flame

which of the following can be used safely to purge tubing before brazing

nitrogen

a street fitting is an angled tube or pipe fitting with

one male end and one female end

for the hottest flame possible which should you use

oxyacetylene torch

an arrangement of compressors stored in the Machinery room and piped in parallel with a common suction line, liquid line, and liquid receiver is a

parallel compressor rack

a pipe strength is based on its wall thickness which is called

pipe schedule

using off-cycle pump down on a commercial refrigeration system is a good method of

preventing compressor flooding

a misting system is most often used in display cases for ________ to prevent dehydration

produce

a system specifically designed to reduce the temperature of cooked food through refrigerated storage temperature is a

quick chiller

after tubing is cut Burrs on the cut ends must be removed by

reaming

a primary benefit of minimizing the distance between the separate parts of a commercial refrigeration system is a significant reduction of

refrigerant charge

to pull a deep vacuum as quickly as possible, what should a technician do regarding Schrader valves

remove the Schrader valve

subcooling may be described as the amount of heat

removed from a refrigerant after it has condensed

to prevent condensation from forming, commercial refrigerated cabinets commonly use what to warm certent outer edges

resistance heating strips

to perform liquid recovery a recovery machine must be equipped with a ______ that flashes liquid refrigerant into a vapor

restriction device

a release valve with an element that bursts before system pressure exceeds an unsafe level is a

ruptured disc

two plastic pipes can be joined through a process called _________ welding, which allows the surface Polymers of each plastic pipe to dissolve and become entangled

solvent

an inverted Ice Cube evaporator

sprays cold water into its molds until ice is formed

a type of strong tubing that is resistant to corrosion and commonly used for food processing milk handling, and other Refrigeration application is ______ tubing

stainless steel

install a ______& to protect a compressor after a burnout

suction Line Filter drier

which of the following is not a type of tool used to swage tubing. A. hydraulic swaging tool B. lever swaging tool C. swaging blade D. swaging punch

swaging blade

when pulling a vacuum, a technician can observe the gas laws and action. For example, in a refrigeration system, as pressure drops,

temperature drops

checking refrigerant charge by subcooling is normally done on systems using

thermostatic expansion valve

true or false CPVC pipe has a maximum service temperature higher than that of PVC pipe

true

true or false a filter drier should be replaced whenever the system is open for service

true

true or false a two-part epoxy compound should only be purchased on an as-needed basis due to its Limited shelf-life

true

true or false mechanical fittings can be used to join two tubes made of dissimilar metals

true

true or false suction Line Filter driers can hinder the return of oil to the compressor

true

true or false there should not be a measurable pressure difference in pressure measurements taken before and after the filter drier

true

true or false? Hand-drawn ACR tubing must be connected by brazing because hard drawn tubing cannot be flared

true

to check whether a recovery cylinder is liquid level switch is working, connect the switch to a recovery machine and Recovery cylinder set up, turn on the machine, and then

turn the recovery cylinder upside down

the pilot valve on a 4-way solenoid valve

uses high pressure Vapor to operate the four-way valve